Method of and apparatus for bleaching paper pulp



Jan. 29, 1929. 4?

- J. RUTHS METHOD OF AND APPARATUS FOR BLEACHING PAPER PULP Filed Oct. 20, l921 Patented J 29,

J'OHANNES at-Jams, or

DJURSHOLM, SWEDEN, ASSIGNOR TO ,RUTHS ACCUMULATOR AKTIEBQLAG, OF STOCKHOLM, SWEDEN. K

METHOD o'F AND APPARATUS non BLEACHING PAPER roar.

Application filed October 20, 1921, Serial No.'5c9,134, and in Sweden January 9, i926.

- In such manufacturing processes where it is required to heat a large quantity of a liquid to. a certain temperature, and where the heating is etfected'by means of steam, one has heretofore been compelled touse a relatively long time for this, owing to the fact that it has been impossible to obtain in a short time the quantity of steam required for the purpose from the boiler battery. in A ain, if the boiler battery were enlarged so t at the process could be finished in a short time, the efliciency of the boiler plant would be considerably lowered in cases where the processes in question are rather ind termittent, as there would then during long periods, be only a very slight load on the' boilers.-

Ta'king as an example the bleaching process in a sulphite factory, this process generally is performed as follows:

[After the bleaching holland'er has been filled'with pulp and bleaching liquor, the

temperature of the liquor is to'be raised to about' lll degrees Centigrade. Thisheating is generally effected by leading steam directly, into the bleaching liquor, which in the case of a bleaching hollander containing about 70 cubic meters requires a time of from 2 to 3 hours.

The present invention has for its purpose to considerably reduce this period, whereby the time of the whole cycle of operations isalso shortened which in turn brings about a corresponding increase in the yield of the plant, besides which the losses due to radiation and cooling are decreased.

This is effected by drawing off the quantity of steam required for the process in a uniform current, which is led into a heat or steam storer having a steam space and a water space, the steam the said storer. steam is then drawn ofi directly to the bleaching hollandeiz. The uantity of steam is now only limited by the ischarging capacity of the storer, and as the same is very great, the time of heating up the liquid can be considerably decreased! Thus it is possible to shorten the heating period from 2 to 3 hours,

50 to to minutes. Moreover, this reduction of time may take place without imposing any furtherload-stresses on the boilers which are entirelyrelieved of all the peak loads that areapt to occur already in a heating period of 2 to 3 hours.

.L a piping being accumulated in- From thls steam storer In fact, according. to. the present inizen- 7 tion, the steam supply from the steam boilers for the bleaching process will be. entirely uniform and constant during the whole time of the cycle of operations. If, before the steam flows into the storer, the same iscaused to pass through a back pressure turbine, or" any other steam consumer, it will also be ossible to obtain power from all this steam. eretofore, this has not been possible.- If

namely the heating has to take place in a reacannot be COl'lStlUCLed to. any economical advantage to receive large quantities of steam at times, andthen to run interveniriglyhndi a comparatively slight load. there is not always a demand for the power which is generated periodically in the manner described. With the arrangement as suggested in this application the supply of vsona'bly short time, the engine in' question Moreover,

steam to the steam motor may, on the other hand, he about'constant, thus causing the power generated also to be constant, such aconstantpower being always utilizable.

In the accompanying drawings forming part of this specification, Fig. 1 shows diagrammatically an arrangement for carrying my invention into effect. Fig. 2 shows a slightly different arrangement in. which a motorsuch-as a back pressure or an extraction turbine is positioned to receive the steam from the boilers before passing to the steam storer. f a

P denotes the boiler battery, A is the storer, leading from the boiler battery into the water space of the storer, the said piping delivering steam into the storer A. V is a valve inserted in the piping L the said valve serving as a means of adjustment for admitting just the desired quantity of steam. B designates a vessel containing the liquid to be heated, in the present case a bleaching hollander. L is a piping leading from the steam space of the storer, and serving as a conduit for steam drawn offfrom the storer and supplied to the bleaching hol- Tdesignates'the engine in- Gil may often be reduced still more by, .the

time of filling the receptacle to simultaneously heat the water.

he'steam used for the heating may then preferably be employed also forintroducing the water or bleachingliquor into the bleaching hollander by means at I claim as new and desire to secure by LettersjPatent of the United States is of an-inj'ectoror the like inserted in the steam 1. A method of short time bleaching of paper pulp which comprises generating steam in uniform quantity, accumulating the steam in a suitable storer and quickly supplying substantially the entirevolume of stored steam to a bleaching h'ollander containing pulp.

2. A method of short time bleachingof paper pulp which comprisesgener'ating steam at a uniform rate, leading steam to a suitable storer, accumulating steam in said storer and simultaneously injecting. bleaching liquor into a hol'lander and heating the liquor by quickly supplying substantially the entire volume of stored steam from the storer.

" bmation, a

apparatus comprising in com leaching hollande'r, a steam storer, a steam boiler, a conduit for conduct ing steam from said boilerto said storer, a valve in said conduit to control flow of steam therethrougli, an injector for quickly discharging the steam from the storer,'a second conduit for conducting steam from said storer to said injector, means to supply liquid to said injector, a third conduit for conducting liquid from lander, and a valve forcontrolling the supply of steam to the injector.

4. A method of short time bleaching of paper pulp which comprises generating a large quantity of steam, generated "steam in a suitable sterer, and quicklysupplying therefrom-the great quan "3. Bleachin titles of steam necessary for the bleachingprocess to a bleaching hollander containing In testimony whereof I afi1x my signature.

' JOHANNES auras,

said injector into said hcl accumulating the 

